• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.5
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• pp.126-134
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• 2020

In the case of an earthquake, the fluid storage structure generates hydraulic pressure due to the fluctuation of the fluid. At this time, the hydraulic pressure of the fluid changes not only the peaked acceleration of the earthquake but also the sloshing height of the fluid free water surface. Factors influencing this change in load include the shape of the seismic wave, the maximum seismic strength, the size of the fluid storage structure, the width of the structure, and the height of the fluid. In this study, the effect of the ratio between the height of the fluid and the width of the structure was investigated on the fluctuation characteristics of the fluid. 200mm and 140mm of fluid were placed in a water storage tank with a width of 500mm, and a real seismic wave was applied to measure the shape of the fluctuation of the fluid free water surface. The similarity between the experiment and the analysis was verified through the S.P.H(Smoothed Particle Hydrodynamic) technique, one of the numerical analysis techniques. It was confirmed that the free water surface of the fluid showed a similar shape, through comparison of experiment and analysis. And based on this results, SPH technique was applied to analyze the fluctuation shape of the fluid free water surface while varying the ratio between the fluid height and the structure width. An equation to predict the maximum and minimum heights of the fluid free water surface during an earthquake was proposed, and it was confirmed that the error between the maximum and minimum heights of the fluid free water surface predicted by the proposed equation was within a maximum of 3%.

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.94-95
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• 2001

본 논문에서는 큰 광학면을 Profilometry로 측정하는데 있어서 꼭 필요한 기준계로 공기 중을 전파해가는 레이저 광선을 이용하는 방법을 논의하였다 Profilometer는 stylus tip이 직접 표면에 접촉하여 높이를 읽어가는 방식으로 이때 기준계는 정확한 높이를 구하는데 아주 중요한 역할을 한다 즉, 높이의 측정은 기준계를 기준 하여 이루어지기 때문에 기준계에서의 오차는 곧바로 높이의 오차로 이어지게 된다. (중략)

• Journal of the Korean Association of Geographic Information Studies
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• v.24 no.2
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• pp.78-90
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• 2021

In order to construct a precision geoid, it has been diversified into land, sea, aviation, and satellite gravity measurement methods, and measurement technology has developed, making it possible to secure high-resolution, high-precision gravity data. The construction of precision geoids can be fast and conveniently decided through GNSS surveys without separate leveling, and since 2014, the National Geographic Information Institute has been developing a hybrid geoid model to improve the accuracy of height surveying based on GNSS. In this study, the results of the GNSS height measurement were compared and analyzed choosing existing public reference points to verify the GNSS height measurement of public surveys. Experiments are conducted with GNSS height measurements and analyzed precision for public reference points on coastal, border, and mountainous terrain presented as low-precision areas or expected-to-be low-precision in research reports. To verify the GNSS height measurement, the GNSS ellipsoid height of the surrounding integrated datum to be used as a base point for the GNSS height measurement at the public datum. Based on the checked integrated datum, the GNSS ellipsoid of the public datum was calculated, and the elevation was calculated using the KNGeoid18 model and compared with the results of the direct level measurement elevation. The analysis showed that the results of GNSS height measurement at public reference points in the coastal, border, and mountainous areas were satisfied with the accuracy of public level measurement in grades 3 and 4. Through this study, GNSS level measurement can be used more efficiently than existing direct level measurements depending on the height accuracy required by users, and KNGeoids 18 can also be used in various fields such as autonomous vehicles and unmanned aerial vehicles.

• Social Workers
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• no.11 s.55
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• pp.49-51
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• 2006

• Journal of the Korean Geosynthetics Society
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• v.18 no.4
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• pp.139-149
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• 2019

For retaining wall designs, horizontal earth pressure induced by traffic loads over the walls is calculated based on equivalent uniform pressure height. The AASHTO LRFD design standards propose equivalent uniform pressure height of traffic loads; however, the equivalent uniform pressure height is calibrated using the US standard trucks. As the domestic standard trucks are different from the US standard trucks, in this study, new domestic equivalent uniform pressure height is proposed using the Boussinesq theory varying vehicle directions, Poisson's ratios of pavement layers, and retaining wall height. The proposed equivalent uniform pressure heights are generally higher than those proposed by the AASHTO design standards because the axle loads and their densities of two domestic standard trucks are higher than those of the US standard trucks. The most highest equivalent uniform pressure height was found for traffic direction perpendicular to longitudinal direction of retaining wall.

• Journal of The Korean Society of Grassland and Forage Science
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• v.8 no.1
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• pp.14-19
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• 1988

This experiment was conducted to investigate the effects of the different cutting height on the changes of nonstructural carbohydrate contents, winter survival, spring yields of Italian ryegrass, tall fescue and pernennial ryegrass swards. It was carried out on the experimental field of Livestock Experiment Station, in Suweon, from Sept. 1986 to May 1987. The results obtained are summarized as follows: 1. The changes in soil surface temperature of plots were slightly appeared among grasses. But not appeared with cutting heights. 2. Nonstructural carbohydrate contents of three grasses until wintering showed much more in line with unclipped, 15 cm cutting and 6 cm cutting height. Among three grasses, Italian ryegrass was highest and tall fescue was lowest. Otherwise, wintering survival was not show the difference among grasses and cutting heights. 3. The green yields was much more producted in line with Iralian ryegrass, perennial ryegrass and tall fescue. But in dry matter yields, it was not significantly different among grasses and cutting heights.

• Journal of Labour Economics
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• v.39 no.3
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• pp.1-32
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• 2016

The purpose of this article is to examine the change of employment expectation using the wave 7-11 (2010-2014) of Korea Education and Employment Panel(KEEP). The three main variables are the reservation wage, which has been studied by labor economists for a long time, the convenient working environment factor, the desired job factor. Last two of which are extracted from the 15 survey questions about employment expectation using the factor analysis. Our estimates suggest that male have a higher reservation wage than female while female have a higher level of expectation overall. Women attach more importance to working environment especially. Also, university students have a higher reservation wage and set a higher value on the desired job than employees and job seekers.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.12C
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• pp.1652-1659
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• 2004

In this paper, we propose the algorithm that automatically measures the height of the object to move on the base plane by using the geometric information. To extract a moving object from real-time images creates the background image and each pixel is modeled by the three values. The extracted region is represented by cardboard model and calculates the coordinate center in the each part. The top and bottom point of an object are extracted by the calculated coordinate center and an iterative computation. The two points, top and bottom, are used for measuring the height. Given the vanishing line of the ground plane, the vertical vanishing point, and at least one reference height in the scene; then the height of any point from the ground may be computed by specifying the image of the point and the image of the vertical intersection with the ground plane at that point. Through a confidence valuation of the height to be measured, we confirmed similar actual height and result in the simulation experiment.

• Journal of the Korean GEO-environmental Society
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• v.20 no.1
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• pp.43-49
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• 2019

In this paper, we introduced phase optimization techniques in the Soil-Nail design to optimize the reinforcement required for each grade level. The optimal design results at the maximum slope height were further amplified to allow for phase optimization of the horizontal spacing of the Nail in accordance with the change in the height of the slope. The limit equilibrium analysis was performed by step-by-step sloping height, and the safety factor exceeded when the horizontal spacing of four days was fixed. The process of optimization was effectively carried out by densifying the required reinforcement depending on the slope elevation. Also limited to reflect the axial force of the nail into the reinforcement details.Using the method, the members' strength was reflected. When phase optimization technique is applied for each slope height by calculating the stiffening precision, it is judged that it will be more economical to optimize horizontal intervals by effectively reducing the repeated reinterpretation process that satisfies the reference safety ratio for each slope height.

• The Journal of the Convergence on Culture Technology
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• v.9 no.1
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• pp.525-530
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• 2023

Although double-stage hanger is used in many homes for its space utilization and ease of installation, it is inconvenient for users to take off clothes hung on the upper bar due to its high height. Therefore, this paper proposes a new type of double-stage hanger that allows users to easily hang or take out clothes hung on the upper bar while maintaining the function of the existing double-stage hanger. 4-bar link mechanism is applied so that the upper bar can come down to a convenient height with one operation. In addition, an appropriate link shape, length, and joint type are selected so that the height is adjusted three-dimensionally to prevent overlapping of clothes hanging on upper/lower bars. FEA analysis is performed to ensure that the presented hanger shape can support the load of clothes during height adjustment and the feasibility of the three-dimensional height adjustment hanger is verified through fabrication.